A Gas Turbine Manufacture asked Navcon Engineering to measure the sound power emission from a Gas Expanding Turbine Package. The sound power test was conducted during the performance test of the equipment.

Typical sound pressure measurements could not be used to determine the sound power of the turbine. The noise environment was dominated by the piping noise from the intake and exhaust piping and the noise from supporting portable air compressor located 20 ft. from the turbine skid. The sound levels from the Gas Turbine Package were approximately 10 to 15 dB below the overall ambient noise level generated by piping and the supporting air compressors.

Acoustic Intensity was the only feasible method to measure and estimate the sound power level of the gas turbine. The sound power emission was calculated using an acoustic intensity method as described in ISO 9614-2, "Acoustics - Determination of sound power levels of noise sources using intensity - Part 2: Measurement by scanning".

Setup of a Control Volume for the Acoustic Intensity Measurement. The sound power test was conducted during the performance test of the turbine.

The scanning method was used to measure a total of 41 surfaces. Each surface was scanned twice (vertical, horizontal).